A variety of liquids are packaged for use in containers which are intended to be inverted to pour the contents into another container where they are ultimately consumed. One common example is motor oil. In order to add motor oil to an engine, the container filled with oil must be aligned with an oil receiving opening provided in the engine for that purpose. In the process of inverting a full container of oil it is common for a portion of the contents to be spilled over the engine and onto the ground. It is undesirable to spill an environmental pollutant liquid, such as oil. However, even when the liquid is not a pollutant it is desirable to avoid spilling liquid for reasons of cleanliness, convenience and waste-minimizing efficiency.
Applicant's prior patent issued under U.S. Pat. No. 5,370,266, which is fully incorporated herein by reference, teaches a method of reducing spillage when pouring liquid out of a container. A free floating buoyant member is placed into a resilient deformable container adapted for containing liquid of greater density than the member such that the member floats upon the surface of the liquid. A fluid flow passage of the container is narrower than the dimensions of the member such that the member is prevented from exiting through the fluid flow passage. In use, a force is exerted to temporarily deform the container, thereby reducing the volume of the inner cavity and causing the liquid in the container to press the member into a position sealing the fluid flow passage. The container is then inverted into a pouring position, where the force upon the container is released such that the container resiliently resumes its original shape thereby increasing the volume of the inner cavity and permitting the member to float away from the fluid flow passage such that liquid freely passes through the fluid flow passage.
In practice, it has been found that while the method significantly reduces spillage by closing off the fluid flow passage until pouring time, the buoyant member that performs this spill-preventing function by blocking the fluid flow passage of the container when the full container is squeezed also blocks a final residual portion of the fluid from exiting the container when the liquid level in the container has been drained to a level no longer sufficient to float the buoyant member away from the fluid flow passage. Residual liquid remaining in the container, particularly liquid tending to cling to the container walls due its viscosity characteristic, therefore remains inside the container, defining a wasted fraction of the original liquid supply and creating environmental and disposal concerns in the case of a hazardous or pollutant liquid.
It is therefore desirable to provide an improved method for reducing spillage during pouring of a liquid from a container that reduces the amount of residual liquid left behind in the container, or in other words increases the overall fraction of the liquid released from the container, relative to prior art pouring methods.